/**
 * Modify the example code shown in Figure 11.4 to pass the structure between the threadsproperly.
 **/
#include <pthread.h>

#include "apue.h"

struct foo {
  int a, b, c, d;
};

void printfoo(const char *s, const struct foo *fp)
{
  printf("%s", s);
  printf("  structure at 0x%lx\n", (unsigned long)fp);
  printf("  foo.a = %d\n", fp->a);
  printf("  foo.b = %d\n", fp->b);
  printf("  foo.c = %d\n", fp->c);
  printf("  foo.d = %d\n", fp->d);
}

void *thr_fn1(void *arg)
{
  /* 方法一：将foo变量设置成静态变量（全局变量也可以） */
  // static struct foo	foo = {1, 2, 3, 4};
  /* 方法二：使用malloc函数 */
  struct foo *foo = (struct foo *)malloc(sizeof(struct foo));
  foo->a = 1;
  foo->b = 2;
  foo->c = 3;
  foo->d = 4;
  printfoo("thread 1:\n", foo);
  pthread_exit((void *)foo);
}

void *thr_fn2(void *arg)
{
  printf("thread 2: ID is %lu\n", (unsigned long)pthread_self());
  pthread_exit((void *)0);
}

int main(void)
{
  int err;
  pthread_t tid1, tid2;
  struct foo *fp;

  err = pthread_create(&tid1, NULL, thr_fn1, NULL);
  if (err != 0) err_exit(err, "can't create thread 1");
  err = pthread_join(tid1, (void *)&fp);
  if (err != 0) err_exit(err, "can't join with thread 1");
  sleep(1);

  printf("parent starting second thread\n");
  err = pthread_create(&tid2, NULL, thr_fn2, NULL);
  if (err != 0) err_exit(err, "can't create thread 2");
  sleep(1);
  printfoo("parent:\n", fp);

  free(fp); /* 可以不加，进程结束回自动回收 */
  exit(0);
}
